Filter-free projector

ABSTRACT

A filter-free projector includes a light source unit to generate light beam with different color and a color control module couple to the light source unit for switching the light source unit to emit one color light at a time. A digital mirror device panel having a plurality of mirror elements is provided so as to reflect light fed from the light source unit. Projection lens is positioned in the reflected light path from the digital mirror device panel to project image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/954,687,filed Nov. 26, 2010, which is a continuation of application Ser. No.11/783,551, filed Apr. 10, 2007, now U.S. Pat. No. 7,874,486.

TECHNICAL FIELD

The present invention relates generally to a projecting module and moreparticularly to a filter free projecting module for portable device or astand alone projector.

BACKGROUND OF THE RELATED ART

Cellular communications systems typically include multiple base stationsfor communicating with mobile stations in various geographicaltransmission areas. Each base station provides an interface between themobile station and a telecommunications network. Mobile telephonesystems are in use or being developed in which the geographic coveragearea of the system is divided into smaller separate cells, itcommunicates with the network via a fixed station located in the cell.Mobile telephones belonging to the system are free to travel from onecell to another. When a subscriber within the same system or within anexternal system wishes to call a mobile subscriber within this system,the network must have information on the actual location of the mobiletelephone.

Recently, the price of cellular telephone has been greatly reduced andbecome affordable to lots of people. It is common that a person ownsmore than one cellular phone. Some people even replace their cellulartelephones as often as they replace their clothes or hairstyle. Thecellular manufactures have to release new models with differentappearances, function and styles more frequently so as to attract theattention of the buyer and occupy a favorable marketing share.Furthermore, the conventional projector employ white light lamp as alight source, therefore, at least two reflector lens and at least threelight-split lens are required to split the white light into three colors(red, green and blue). The optical lens set is expensive. The mechanismof the optical system is too complicated and the size can not bereduced. Further, the lamp source will generate heat with hightemperature. Another type projector is called digital light projector,U.S. Pat. No. 6,733,137, U.S. Pat. No. 6,988,808 disclose suchprojector. The type of projector employs DMD (digital micro-mirrordevice) and a color wheel for projecting. The digital mirror device hasseveral hundreds of thousand of mirror elements and it is capable ofreducing a difference in chromaticness (tint) caused byperformance/characteristic variation between filters or between lightsources. A driving unit controls an inclination of each of mirrorelements of a DMD panel according to a corrected video signal and arevolution state of a color filter wheel and wherein the correcting unitcorrects luminance signal for each color of video signals by calculatinga relative intensity of light having passed through each filter makingup the color filter wheel using the output of a photosensor occurringwhen each mirror element of the DMD panel is put in the OFF state. Thecolor filter wheel is driven by a motor and it's size is not small,consequently, it is unlikely to embedded the projecting device into aportable device. Further, the conventional technical employs white lightas the light source and it generates high temperature heat duringoperation. The projector needs a lot of lens to cooperate with the lightsource and the color filter wheel as well. Low-frequency flashing effectwill occurs due to the white light passing through the high speedrevolution color wheel which is driven by the motor. As recognizedherein, for portability, it is desirable to configure the projector tobe as slim as possible. But the goal of size reduction is frustrated bythe present of the elements mentioned above.

SUMMARY

The object of the present invention is to provide a filter freeprojector (FFP) with color light source.

The filter-free projector comprises a light source unit to generatelight beam with different color; a color control module couple to thelight source unit for switching the light source unit to emit one colorlight at a time; a digital mirror device panel having a plurality ofmirror elements each being controlled so as to reflect light fed fromthe light source unit; projection lens positioned in the reflected lightpath from the digital mirror device panel to project image. The lightsource unit includes organic electroluminescence element, LED element,field emitting element laser diode or electroluminescence element toemit illumination of red, green, or blue. The filter free projectormaybe embedded into a portable device including cellular, notebook, GPS,PDA, game player, media player, video camera or still camera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a projector and FIG. 1A, 1B show the diagramof the color light source unit according to the present invention.

FIG. 2 shows a diagram of a color light source unit according to thepresent invention.

FIG. 3 shows a diagram of field emitting device according to the presentinvention.

FIG. 4 shows a diagram of EL emitting source according to the presentinvention.

FIG. 5 shows a diagram of a mobile phone with projector according to thepresent invention.

FIGS. 6 and 7 show diagrams of a image capturing device and media playerwith projector according to the present invention.

FIG. 8 shows a diagram of a computer (or notebook) with projectoraccording to the present invention.

DETAILED DESCRIPTION

The present invention relates generally to a projecting module forportable terminal or stand alone projector. The portable terminalincludes but not limited to cellular phone, PDA (personal digitalassistant), smart phone, notebook, medium player (MP3, MP4), GPS and theequivalent thereof.

FIG. 1 is a diagram illustrating main components of a filter freeprojector using a DMD (Digital Micro-mirror Device) panel according toan embodiment of the present invention. The filter free projector 1000of the embodiment, as shown in FIG. 1, includes a light source unit1100, a DMD panel 1200, and projection lens 1300. Some elements (such aslens amplifier, converter, correcting section and driving section) maybe necessary. In one embodiment, lens amplifier may be located betweenthe light source unit 1100 and the DMD panel 1200. However, they are notthe feature of the present invention, thus the description is omitted.In the embodiment, the DMD panel 1200 includes a plurality ofmicro-mirror elements (not shown) and controlled by the driving section.The driving section produces image light to be projected onto the screenand the inclination state of each of the mirror elements (not shown) isaccording to a switching state of the color light source state. Thelight source unit 1100 may emit mono-light with red, green or blue,respectively. A color control module 1400 is coupled to the light sourceunit 1110 to determine which color of light will be emitted. The signalto be fed in from the correcting section and the inclination state ofeach of the mirror elements is cooperated with the alternation state ofthe color light source unit 1100. The color control module 1400 isemployed to switching the colors and it may be formed by integratedcircuits. The switching frequency should be higher than the one of theimage signal. The switching time of the color is far faster than thewheel of the prior art. It reduces time required for switching colors inthe color wheel of prior art. The switching of the color light unitcauses the light to be emitted in order of the red, blue, and greencolors and the switched light is output to DMD panel 1200. Preferably,the color control module 1400 make the light source unit 1100 to emitthe read, blue and green color light with sequence and repeat. The orderof the color can be altered. The color light source unit 1100 has pluralcolor segments and if desired for brightness white segment. Preferably,the unit 1100 includes red color segment, followed by green segment,which in turn is followed by blue segment. In order increase imagebrightness, each blue segment may be followed by a white segment. TheDMD 1200 receives an input signal with a gray scale signal used tocontrol an inclination of each of the mirror elements according to agray scale of each video signal. Thus, each frame of gray scale imagewill be reflected with the R, G, B colors one by one. Thus, theswitching frequency of the sequence light color control module is higherthan the frequency of the video signal. Namely, the frequency of theeach color light is at least triple times of the one of the videosignal. If four colors are employed, then, the frequency will be fourtimes. The multiple frequency of the color control module will make sureeach frame of the image will be processed with R, G, B.

The light source unit 1100 insides electrical discharge lamps such asmetal halide lamps, or halogen lamps, could be used in the light sourceunit. In preferable embodiment, please refer to FIG. 2, the filter freeprojector comprises three light emitting sources 210R, 210G, and 210B isemployed and positioned in correspondence with the DMD 1200,respectively. In one embodiment, the light emitting sources 210R, 210G,and 210B are organic EL (electroluminescence) elements. These organic ELelements are electric-field light emitting thin films that capable ofemission of red, green, and blue light. The DMD 1200 is positioned onthe light-incidence side. The projection lens 1300 could be made up of aplurality of lenses. Thus, the data or file stored in the memory of thedevice or external device can be projected on a screen or wall. Itallows the user to project the image, game or file on an externalscreen. The EL element is small, flat form, light weight, therefore, itallows the small projection to be integrated in the portable device. Thelight source unit can be formed by three mono-light EL devices or asingle EL device which may emit three mono-lights. In another case, theunit 1100 may include light emitting sources 210W for emitting whitelight. The light emitting source may be made of thin film, and thereforeit can be embedded into the portable device.

The digital mirror device panel having a plurality of mirror elementseach being controlled so as to be put in a first inclination state andin a second inclination state and reflecting light fed from the lightsource unit and switched by the control module while being put in thefirst inclination state. A driving unit is used to control so as to puteach of the mirror elements in the digital mirror device panel in thefirst inclination state or the second inclination state according to acorresponding video signal and a switching state of the color controlunit. A correcting unit is used to receive a video signal and thevoltage obtained by photoelectric conversion device, to correct thevideo signal, based on the received voltage and to output the correctedvideo signal to the driving unit. The color control module 1400 isconfigured to include a red, a green and a blue color light source formaking image light of the plurality of colors. As know in the art, theprojector may include digital signal processor mounted on a DLP circuitsboard. However, it is not the feature of the present invention, thedescription is therefore omitted.

Alternatively, another embodiment of light source is shown in FIG. 4, itis a cross-sectional view of the field emission device (FED) accordingto the embodiment of the present invention. As seen in FIG. 3, atransparent substrate 400 is provided and transparent electrodes 420 areformed on the glass substrate 400. The transparent electrodes 420 may bemade of indium tin oxide (ITO) and may be used as the emitterelectrodes. Stacked gate 410 that cover a portion of the transparentelectrodes 420 are formed on the glass substrate 400. Emitters 460 thatemit electrons are formed on a portion of the transparent electrode 420.Each stacked gate 410 includes a mask layer 440 that covers a portion ofthe transparent electrodes, and is formed by UV photolithograph mask.The mask layer 440 is preferably transparent to visible light, butopaque to ultra violet rays and can be made of an amorphous siliconlayer. The silicon layer will be transparent when the thickness is thinenough. A stacked gate 410 structure includes first insulating layer/agate electrode/a second insulating layer/focus gate electrode,sequentially formed over the substrate. The gate insulating layer ispreferably a silicon oxide thin film with a thickness of 2 mu·m or moreand the gate electrode is made of chrome with a thickness of about 0.25mu·m. The gate electrode is used for extracting an electron beam fromthe emitter. The focus gate electrode performs as a collector forcollecting electrons emitted from emitter so that the electrons canreach a fluorescent film 480 disposed above the emitter 460. If thedevice is used for display, the substrate can be silicon or transparentsubstrate. Referring to FIG. 3, a front panel 450 is disposed upward andabove the stacked gate. A variety of visual images are displayed on thefront panel 450. A fluorescent film 480 is attached to a bottom surfaceof the front panel 450 that faces the stacked gate and a direct currentvoltage is applied to the fluorescent film 480 to emit color fordisplay. The fluorescent substance may emit color light by mixing theemitted light if the thin film with R, G, B fluorescent substances.Preferably, the present invention includes three such emission displaysthat separately display image in red components, green components, andblue component (namely, red, green and blue images). The fluorescentsubstances emit red, green, and blue visible light when excited by theelectron beam is evenly distributed on the fluorescent film 480. Spacerseparating the front panel 450 from the stacked gate is a black matrixlayer and is not shown for convenience. Due to the thin film display ifformed with thinner thick and the power consumption is lower than LCD,the present invention may provide smaller size, lighter weight device.The life of battery may last longer. The field emission device does notrequire complicated, power-consuming back lights and filters which arenecessary for LCD. Moreover, the device does not require large arrays ofthin film transistors, and thus, a major source of high cost and yieldproblems for active matrix LCDs is eliminated. The resolution of thedisplay can be improved by using a focus grid to collimate electronsdrawn from the microtips. Preferably, the emitter includes a carbonnanotube emitter to further reducing the device size. Further, thedisplay may omit the liquid crystal material. Further, the fieldemission display does not require the S/D regions which are required byTFT for LCD. Preferably, LED source may irradiate mono color light.Namely, blue light, red light and green light LEDs are employed to actthe light source. In one case, the LED may be formed in a matrix orlinear configuration. Please be noted that the elements with fluorescentsubstances shown in FIG. 4 (carbon nanotube field emission device if theemitter is formed by carbon nano-tube) and FIG. 4 (EL) can be used aslight source as well. Similarly, the light source unit can be formed bythree mono-light FED (or EL) or a single FED (EL) which may emit threemono-lights. One of the reference of organic EL display may refer toU.S. Pat. No. 6,023,371, entitled “Color conversion material, andorganic electroluminescent color display using the same”. Please benote, laser diode maybe used as the light sources. Alternatively, thecolor light source unit 1100 may be composed of a laser 1100 B and acolor conversion module 1100A posited on the light path of the laser.Preferably, color conversion module 1100A may be achieved by anefficient laser wavelength conversion technology, which enables thegeneration and conversion of new laser wavelengths via material'snonlinearity character. Based on engineered microstructures withinferroelectric nonlinear materials, a quasi-phase-matching (QPM) isgenerated to compensate the phase-velocity mismatching betweeninteraction waves for efficient wave-mixings. The QPM enableslaser-based R, G, B display application. In order to achieve efficientwavelength conversion, phase matching between interaction waves arerequired. This has been done in nonlinear materials throughbirefringence phase matching techniques, which orient crystal axis to aspecific angle to achieve phase matching condition for specificinteraction wavelengths. U.S. Pat. No. 7,170,671, entitled “Highefficiency wavelength converters” disclosed one method of the wavelengthconversion. For example, the color conversion module 1100A may includewaveguide with multiple grating with different periodic pattern as shownin FIG. 1B. The color conversion module may include waveguide device orbulk device. The grating could be uniform grating, multiple grating,cascade grating, fan out grating and chirped grating. The lasersequentially provides the radiation to the color conversion module1100A, whereby converting the incident light into R, G, B, respectively.

In another embodiment, the light source of FIG. 4 includes a transparentelectrode 510 on a transparent substrate 500. A fluorescent film orpower 520 is attached to an upper surface of the lower transparentelectrode 510. Preferably, the fluorescent substance emits color light.The present invention includes three such devices that separately emitlight in red components, green components, and blue component. Eachirradiates single color light. Different powder will emit differentcolor. An upper transparent electrode 530 is formed on the fluorescentfilm or power 520. A second transparent substrate 540 is formed on thetransparent electrode 540. A bias is applied on the electrodes to injecthole and electron, thereby exciting the fluorescent substances by thecombination of the electron and hole to emit red, green, or blue visiblelight depending on the compound of the fluorescent substances. Theelements may refer to ELP. In the examples, the light emitting device(LED) can be employed as light source as well and the mechanism andprocess is simpler than prior art. Preferably, LED sources thatirradiate blue light, red light and green light LEDs are employed as thethree mono-color light sources.

From above, the color filter wheel, high temperature white light sourceand a lot of lens such as condense lens are removed from the presentinvention. Therefore, the thermal issue, huge size and flashing effectare solved by the present invention. Furthermore, the present inventionemploys thin film as cold light source, no high temperature thermalissue, the lift time of the source is longer than the white light sourceof prior art, motor vibration noise is omitted. The poser consumption isfar lower than the prior art and it may be integrated into small volumeportable device. The light having undergone switching in such a mannersuch as that the light has any one of the red, blue, and green colors bythe color control module and travels toward the DMD panel 1200 and itsluminous flux maybe calibrated by relay lens (not sown) so that thelight is effectively applied to the DMD panel 1200. The light applied tothe DMD panel 1200 is incident on each of the mirror elements as know inthe art. The DMD 1200 receives an input signal with a gray level signalused to control an inclination of each of the mirror elements accordingto a gray level of each of the red, blue, and green colors representedby a video signal. The correction method and the control a state ofinclination of mirror is well known in the art. Each image light isobtained by operating mirror elements of the DMD panel 1200, therebyprojecting single picture element on the screen. Since switching of thecolor light source unit is sufficiently fast, previous light stays as anafterimage detected by human eyes and almost no case occurs in which acolor looks to have been decomposed. In the present invention, thelights should be directed to the entire DMD and the present inventionemploys an order and sequence light color control module coupled to thelight source unit for emitting different color light, sequentially.During the persistence of vision, the afterimage is thought to persiston the retina.

The present invention may be integrated into a portable device forexample, cellular. FIG. 5 shows a block diagram of a portable terminalwith SIM card connector 130 to carry the SIM card 135, it is well knowin the art, the SIM card is not necessary for some other type ofcellular such as PHS system. The diagram is used for illustrating andnot used for limiting the scope of the present invention. The portableterminal or device 10 includes a RF module. As know in the art, the RFmodule includes antenna 105. This antenna 105 is connected to atransceiver 110, which is used to receive and transmit signal. AS know,the RF module further includes CODEC 115, DSP 120 and A/D converter aswell. Due to the RF module is not the feature of the present invention,therefore, the detailed description is omitted. The present inventionincludes a central control IC 100, an input unit 150, a build-in display160, OS 145, and memory 155 including a ROM program memory, a RAM memoryand a nonvolatile FLASH memory. The RF module may perform the functionof signal transmitting and receiving, frequency synthesizing, base-bandprocessing and digital signal processing. The SIM card hardwareinterface is used for receiving a SIM card. Finally, the signal is sendto the final actuators, i.e. a loudspeaker and a microphone 190.

Moreover, the portable terminal according to the present invention shownin FIG. 5 includes the projecting module 1500. An embodiment is nowdescribed with reference to FIG. 1. A projection display module 1500 iscoupled to the control IC 100. The projection lens 1300 could be made upof a plurality of lenses. Thus, the data or file stored in the memory ofthe device can be projected on a screen or wall. It allows the user toproject the image, game or file on an external screen. The EL element issmall, flat form, light weight, therefore, it allows the smallprojection to be integrated in the portable device. Similarly, theprojecting module could be integrated into a notebook, PDA, videocamera, digital still camera, game player or media player.

The projector or the portable device may include a wireless transferringmodule 1500 coupled to the central control unit 100 for transferringdata wireless and it maybe employed to transfer data between thehand-held device and an external device such as access point or computer(local or remote terminal) via network. In one embodiment, the wirelesstransmission module 1500 for short range refers to WLAN (wireless localarea network) module. As known, the WLAN may transfer data, informationbetween the device and the external device. Thus, the device 10 mayemploy the wireless transmission module 1500 to exchange data. Thewireless transmission module 1500 is compatible to the WiFi, 802.11standard (802.11a, 802.11b, 802.11g, 802.11n), Bluetooth standard orWiMax. In general, the wireless transmission module 1500 allows thedevice 10 couple to the internet via access point, gateway or computer.Thus, the user may download the material, data, image, game, audio,video from internet and project the download data on the screen.

Further, referring to FIG. 6, the device includes a main body having aprocess 402; a display 404 formed on the main body and coupled to theprocessor 402; an image capture element 406 formed within the main bodyand coupled to the processor 402; a memory 408 coupled to the processor;a lens mechanism 310 formed on the main body, coupled to the processor402 and corresponding to the image capture element 406; the projectingmodule 1000 is coupled processor of the portable device so as to projectthe captured image on a screen.

If the projecting module 1000 is employed for medium player such as MP3player, MP4 player, the player includes an analog/digital (A/D)converter 202 for converting analog audio signals into digital audiosignals. The analog audio signals can come from an audio source coupledto player 200. A digital signal processor (DSP) 204 or an audio and/orvideo driving module 206, for instance MP3, MP4 codec, are coupled toA/D converter 202 to receive the digital audio signals. In oneembodiment, MP3 or MP4 codec 206 executes a firmware that includes aMPEG audio layer (e.g., MP3, MP2, or both) codec or video codec (e.g.,MP4), and DSP 204 executes a firmware that includes a different type ofaudio codec (e.g., WMA, ACC, or both). In one embodiment, the firmwarefor DSP 204 also includes a video codec for encoding and decoding videos(e.g., MPEG-4 V1/V2/V3, DivX 3.11/4.0/5.0, Xvid, AVI/ASF, or anycombination thereof). MP3 (or MP4) codec 206 and DSP 204 are coupled toa nonvolatile memory 208 that stores the compressed audio data. The usercan select an audio file from nonvolatile memory 208. DSPs 204 and 206are coupled to an audio processor 210, which processes the digital audiosignals according to default settings or user instructions. Audioprocessor 210 is coupled to a digital/analog (D/A) converter 212, whichconverts the digital audio signals into analog audio signals for theuser. A display 214 is coupled to the DSP 206.

As shown in FIG. 8, wherein the projecting module 1000 can be integratedinto the portable computer system comprises: a processor 800 formedwithin the portable device; a keypad 802 formed on the portable device;a display 804 coupled the processor; a memory 806 coupled to saidprocessor 800. The device further includes an application and/or OS 808and hard disc 810 coupled to the processor. It further includes the WLANmodule 1500 and the projecting module 1000.

As will be understood by persons skilled in the art, the foregoingpreferred embodiment of the present invention is illustrative of thepresent invention rather than limiting the present invention. Havingdescribed the invention in connection with a preferred embodiment,modification will now suggest itself to those skilled in the art. Thus,the invention is not to be limited to this embodiment, but rather theinvention is intended to cover various modifications and similararrangements included within the spirit and scope of the appendedclaims, the scope of which should be accorded the broadestinterpretation so as to encompass all such modifications and similarstructures. While the preferred embodiment of the invention has beenillustrated and described, it will be appreciated that various changescan be made therein without departing from the spirit and scope of theinvention.

1. A filter-free projector comprising: a light source unit to generatelight beam with different color; a sequence light color control modulecoupled to said light source unit for switching said light source unitto emit different color light with order and sequence; a digital mirrordevice panel having a plurality of mirror elements each being controlledso as to reflect light fed from said light source unit; and projectionlens positioned in the reflected light path from said digital mirrordevice panel to project image.
 2. The projector of claim 1, wherein saidlight source unit includes organic electroluminescence element to emitlight of red, green, or blue.
 3. The projector of claim 1, wherein saidlight source unit includes LED element to emit light of red, green orblue.
 4. The projector of claim 1, wherein said light source unitincludes field emitting element to emit light of red, green or blue. 5.The projector of claim 1, wherein said light source unit includes carbonnanotube emitting element to emit light of red, green or blue.
 6. Theprojector of claim 1, wherein said light source unit includeselectroluminescence element to emit light of red, green or blue.
 7. Theprojector of claim 1, wherein said light source unit includes laserdiode to emit light of red, green or blue.
 8. The projector of claim 1,wherein said light source unit includes laser and color conversionmodule to emit light of red, green or blue.
 9. The projector of claim 1,wherein said color conversion module includes waveguide with multiplegrating with different periodic pattern.
 10. The projector of claim 1,further comprising a wireless transferring module coupled to saiddigital mirror device panel.
 11. The projector of claim 10, wherein saidwireless transferring module is compatible to the WiFi, 802.11 standard(802.11a, 802.11b, 802.11g, 802.11n), Bluetooth standard or WiMax. 12.The projector of claim 1, wherein said filter free projector is embeddedinto a portable device including cellular, notebook, GPS, PDA, gameplayer, media player, video camera or still camera.
 13. The projector ofclaim 12, wherein said portable device includes a wireless transferringmodule that is compatible to the WiFi, 802.11 standard (802.11a,802.11b, 802.11g, 802.11n), Bluetooth standard or WiMax.